Base MEter Readings

The DB said:

The stats that most people care about are R which is Impedance, and X which is Reactance. An X of 0 is Resonance. Together R and X make up what is known as Complex Impedance, generally written as R±jX. Explaining their relationship can get complicated from this point.

The Z is actually referred to as "The magnitude of Z" and is properly written as |Z|, although many antenna analyzers just use the letter.. Together with the phase angle (or "PHASE" from above) is another way of getting to the same point as R and X written about above, and is simply another way of writing out the Complex Impedance. Most people in the hobby world don't use these.

RL is return loss. What this represents is the amount of signal that was transmitted that did not make it back to the measuring device, essentially the loss of the signal, and it is always represented as -dB. Many people make the mistake of this "return loss" as being how much of the signal was radiated, which isn't completely false, but they often don't consider that this is also factoring in losses in the antenna system. If your Return Loss goes up, it could be an increase in either of both, and likewise if it goes down it could be a decrease in either or both. Just like lower SWR does not necessarily mean your antenna is performing better, a greater Return Loss does not necessarily your antenna is performing better. It is heavily influenced by SWR, and is considered by many to be another way to show what SWR is showing. This can be useful for things like measuring the losses of a run of coax and such if you know how.

L is inductance, or the measurement of a coil, and is measured in Henrys, which is H for short. In the list you gave, nH would be nanoHenrys, which is 0.0000000001 of a henry.

C is capacitance, essentially the capacitor version of L above and is measured in Farads. Again nF is nanoFarad, and is as nanoHenry above.

At first glance, I don't see anything significantly wrong with what you have posted. Some people would tell you to get X to 0, but you won't notice a difference in performance from where you are now if you do that.

Do you have any questions on any of this?


The DB

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Eldorado828 said:

I'm getting out a pen and pad because I need schooled on this too. I'll be using a rigexpert and need to learn how to properly use it. I've always tuned with a simple swr meter but this brings a whole new light on things.

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The DB said:

That is actually a difficult question to answer. You will note that it has been unanswered on what is to my knowledge the most technical hobby forum around for over a day now.

If SWR is what you care about, you try and get R as close to 50 as you can, and get X as close to 0 as you can.

Some people like to get reactance to be as low as possible instead, which is X = 0 no matter what R is because X = 0 means "Resonance". While this sounds good at first glance, I have never actually seen any evidence that supports this, in fact, I have rarely seen peak gain line up with either SWR or Resonance. I will say this though, this method will almost always get you closer to peak performance.

When operating, you will not notice a difference in performance between these two methods, so take your pick. I don't fault anyone for using either of these.

However, if you are specifically looking for peak performance, you are using the wrong tool. The fact of the matter is, the only way to tune your antenna system for peak performance is to use an external device like a field strength meter, and don't waste your time with an s-meter, they simply aren't accurate enough. Even using such a device, you will almost never notice a real world difference between using a field strength meter and the methods mentioned above.

Beyond here, it gets very complex very fast.


The DB

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Eldorado828 said:

That's definitely a step in the right direction of some understanding for me so it's much appreciate. So I finally got to purchase a rig expert AA-54 and just in playing with it I see it's really cool to see the swr curve but the rest of the information at first glance is Chinese to me so your answers helps a lot. I'll have to admit I'm completely ignorant so the device to me is only as good as I know hot to use it. It's a pretty loaded little device and with a little learning I'm sure hoping to use it to full advantage.

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